1. Field of the Invention
The present invention generally relates to the field of pressurized dispensing containers and is more specifically directed at the improved method and apparatus for releasing additional ingredients into a pressurized dispenser.
2. State of the Prior Art
Applicant is aware of the following patents directed to pressurized dispensing containers:
U.S. Pat. No. 3,235,137 to Bonduris for a pressurized container particularly useful for dispensing shaving cream in which a supply of liquified propellant gas is enclosed by a flexible diaphragm or bag which expands as the supply of shaving foam ingredients is used up to fill the increasing head space. As a result, the remaining ingredients are kept under generally constant pressure within the can to assure even and complete ejection of the same.
U.S. Pat. No. 3,949,911 to Morane for a container pressurizable by heat activation. In this patent the product is initially unpressurized. A supply of propellant in liquified form is sealed in a cartridge located within a flexible pouch within the product container. The container is pressurized by rupturing the cartridge to release the propellant within a gastight pouch which expands within the container to pressurize the same. A preferred method of rupturing the cartridge is by heating the entire container with the product and propellant cartridge within it.
U.S. Pat. No. 2,671,424 to Herring et al. teaches a device for indicating when the contents of a container has been nearly exhausted. A container filled with a fluid under pressure has a capsule containing a colored substance. The capsule is provided with a diaphragm designed to rupture when the internal pressure of the container falls below a level corresponding to near exhaustion of the fluid contents. At that time the colored substance in the capsule is released for admixture with the remaining contents of the container to indicate to a user that the contents are nearly depleted.
U.S. Pat. No. 3,718,236 to Reyner et al. discloses a container wherein a series of bags are ruptured in sequence as the product is used up, each bag releasing additional gas generating substances for repressuring the container. However, the gas is contained within the bags and is not released into the product compartment.
Additionally, applicant has knowledge of the following patents: U.S. Pat. No. 3,178,075 to Riedl et al.; U.S. Pat. No. 3,245,582 to Roth et al.; U.S. Pat. No. 4,062,475 to Harris et al.; U.S. Pat. No. 4,202,470 to Fujii; and U.S. Pat. No. b 3,244,331 to Kharasch.